1. Field of the Invention
The present invention relates generally to the field of spas and whirlpool baths and more specifically to a suction fitting component thereof, which is designed to prevent serious accidents resulting from the trapping of hair and the like which can result in drowning.
2. Prior Art
Whirlpool baths and spas commonly use a plurality of venturi-type jets which mix air and water and propel the combination into a tub filled with water. A pump is normally used to suction water from the interior of the tub and force it through the jets which employ the well-known venturi effect to entrap air as well, to create a bubble-type forceful spray of water for massage and the like. In order to facilitate the withdrawal of the water from the tub by the pump, whirlpool baths are provided with what is called a suction fitting which is positioned within a hole in the wall of the tub at a height below the water surface and which is connected to the pump inlet so that the force of the pumping action sucks the water out of the tub through the hole and the fitting. Typically, the face of the fitting, which is readily visible in the interior of the tub, is configured to provide a protective covering that has a plurality of small apertures. Such a configuration allows water to be sucked through the small apertures of the suction fitting, but attempts to prevent hair and body parts, such as elbows and the meaty part of the body from being sucked into the suction fitting which may hold the individual against the wall adjacent the suction fitting and cause an accident or other discomfort.
Unfortunately, it has been found that even with the small orifices in the cover of the suction fitting, accidents can still happen and in fact, do happen, some resulting in drowning. Such accidents may result from the trapping of hair of an individual whose head is below the surface of the water. The hair may be sucked through the small apertures and be trapped in the suction fitting, thereby preventing the person whose hair is trapped, from being able to stand and remove his head from adjacent the suction fitting. This severe problem of a potential drowning accident has resulted in certain attempts to solve that problem by divising systems which sense the blockage of the suction fitting cover and turn off the pump when that occurs, so that the negative suction pressure falls to zero, the hair can be released and the person can stand and avoid accidental drowning. An example of such prior art is disclosed in U.S. Pat. No. 5,167,041 to Burkitt. The Burkitt patent discloses a suction fitting having a suction line connected to the pump for circulating the water in the tub and also having a pressure sensor line connecting to a water level sensor, which is, in turn connected to the pump control which is connected to the pump for turning it on and off in response to the level sensor. The water level sensor is a float assembly having a float which moves up and down within a chamber, the float's motion being determined by the water level in the tub when the suction assembly is unblocked. On the other hand, when the face of the suction assembly is blocked, a plurality of slots in the protective cover permits the suction effect of the pump to pull water through those slots. The water exits from the sensor line, thereby reducing the water level in the float chamber, activating a switch, which in turn turns off the pump, thereby reducing the suction level to zero and permitting the blockage to be removed. While the Burkitt disclosure describes a device which can overcome the prior art safety hazard described above, it suffers from a number of disadvantages which can still have a significant effect on the actual safety of the device, as well as on other commercially important features of the suction assembly. By way of example, the Burkitt device relies on a plurality of elongated slots in the protective cover of the suction fitting. These slots radiate from the central opening of the suction assembly cover to a plurality of suction openings in the face or cover of the suction fitting, separated from the central opening thereof. Unfortunately, this safety feature assumes that whatever is blocking the face of the suction fitting, will not also block the passage of water within these slots. However, the most common material that may block the face of a suction fitting of the type herein described is human hair and human hair is flexible enough, soft enough and fine enough to also block the slots of the Burkitt device and thus impede the safety function thereof. Furthermore, these slots in the face or cover of the suction fitting of the Burkitt disclosure may detract from the aesthetic appearance of the cover and therefore become unattractive from a commercial standpoint. Furthermore, a safety cover with slots is more difficult to mold in plastic or form in sheet metal and more difficult to plate, such as plating with various coatings, including metal coatings, to give the face a particular metal appearance such as a gold or silver appearance, which is common in the whirlpool bath industry. Furthermore, the Burkitt device is dependent for its proper operation on the use of the float chamber and a pair of switches mounted on the outside of the float chamber, which must operate properly and reliably for the pump to be turned off in response to the position of the float within the chamber. However, it is well-known that switches, particularly magnetic switches, can be unreliable and therefore either cause the safety feature of the Burkitt device to fail or to turn off the pump when there is no reasonable basis for doing so (i.e., even when the face of the suction fitting is not blocked).
Thus, despite the disclosure of U.S. Pat. No. 5,167,041 to Burkitt, there is still a continuing need for a safety device for suction fittings for use in whirlpool baths which overcomes the disadvantages noted above. More specifically, there is still a need for a device which can turn the pump off whenever the face of the suction fitting is blocked, without requiring the use of slots in the tub interior face of the suction fitting, without requiring that the face have special slots which detract from its aesthetic appearance and without requiring that the face have slots which can increase the difficulty of plastic molding or metal forming and plating which can otherwise increase the cost of such devices. Most importantly however, there is still a continuing need for a suction fitting pump turn off mechanism which does not depend on moving parts or potentially unreliable electrical, mechanical or magnetic switches which can either fail to operate when required to or operate when it is unnecessary.